The present invention relates to an assembly for anchoring objects to a supporting structure, for example of masonry.
Fastening assemblies of the type under discussion are so-called expansion anchor devices which are known and have been disclosed in a number of applicant's U.S. Pat. Nos., for example 3,964,230; 3,968,721, etc.
A fastening or anchoring assembly of the type under consideration comprises an anchoring threaded bolt, an expansion sleeve and an expander body insertable into the expansion sleeve to outwardly expand the latter to fasten the assembly at the base of the borehole provided in the supporting structure, e.g. masonry. The expander body is normally formed as an expander cone. The expansion sleeve has the end face which faces the expander cone. Elongated slots are provided in the expansion sleeve at said end face, which slots make it possible during the driving-in of the expansion body, the expansion of the sleeve. An inner thread, into which a fastening screw is screwed in to fasten a desired object to the outer face of the masonry, can be provided at the other end of the threaded bolt.
To ensure that the expansion sleeve can spread out or expand during the insertion of the fastening screw, it is required that the expander cone can be pulled into the expansion sleeve. This is possible only when the inner thread provided in the anchoring bolt is sufficiently spaced in the borehole from the outer face of the wall. Only in such case is it possible to pull the anchoring or fastening assembly in the direction of the wall outer face whereby the expander cone would be able to pull into the expansion sleeve rigidly supported in the borehole.